query_question: The many identical residents of Whoville love drinking Zlurp. Each resident has the following willingness to pay for the tasty refreshment:<image 1>The cost of producing Zlurp is $1.50, and the competitive suppliers sell it at this price. (The supply curve is horizontal.) Mayor Grinch imposes a $1 tax on Zlurp. What is the external cost?
options: ['1', '2', '3', '4']
demo_question_list: The graph below shows the supply and demand curves and the world price for bagels. <image 1> What is the equilibrium quantity if this country does not trade?
  A. 2
  B. 4
  C. 6
  D. 8
  
  Answer with the option's letter from the given choices directly. A recent study found that the demand and supply schedules for Frisbees are as follows:<image 1> What are the equilibrium quantity of Frisbees?
  A. 6 million
  B. 7 million
  C. 8 million
  D. 9 million
  
  Answer with the option's letter from the given choices directly. The table below describes production possibilities for Mexico and Nigeria. Each number in the table shows the number of workers needed to produce one unit of the product. <image 1> Suppose that both countries have 90 workers. Which country should be specializing in the production of Shoes?
  A. Nigeria
  B. Neither country
  C. Mexico
  
  Answer with the option's letter from the given choices directly. The graph below shows the AD-AS diagram for Spain. All numbers are in billions. <image 1> What is the price level in the short-run equilibrium?
  A. 500
  B. 450
  C. 400
  D. 600
  
  Answer with the option's letter from the given choices directly.